Fmoc-[15N]Val-OH

Fmoc-[15N]Val-OH is an Fmoc-protected, nitrogen-isotopically labeled valine building block in which the α-amino nitrogen is enriched with 15N while the side chain retains the isopropyl stereochemical framework of L-valine. The molecule combines an Fmoc carbamate on the nitrogen with a free carboxylic acid, enabling compatibility with standard solid-phase peptide synthesis workflows where orthogonal deprotection and amide bond formation are required. The labeled 15N center provides a direct handle for isotope-resolved NMR, MS fragmentation interpretation, and peptide backbone tracing, while the valine side chain supports hydrophobic packing motifs in peptide and peptidomimetic structures. The presence of a protected amine and an unprotected acid makes the compound a practical chiral amino acid intermediate for downstream coupling, analytical standards, and isotope-tagged biochemical probes.

1. Isotope-Labeled Peptide Synthesis

Fmoc-[15N]Val-OH is applied in peptide synthesis for producing 15N-labeled valine residues that enable backbone-specific tracking in NMR and mass spectrometry workflows. The Fmoc carbamate protects the amino group during chain assembly, while the free carboxylic acid participates in peptide coupling after Fmoc removal, supporting controlled formation of amide bonds with neighboring residues. The stereochemical identity of the L-valine side chain allows incorporation into sequence-defined peptides that maintain realistic conformational preferences. The resulting isotope-tagged peptides serve as research-grade materials for mechanistic studies, conformational analysis, and isotope-resolved structural characterization.

2. NMR And MS Structural Probes

Fmoc-[15N]Val-OH functions as an isotope-enriched chemical probe for analytical research targeting nitrogen-sensitive spectroscopic assignments. The 15N label on the α-amino nitrogen yields enhanced interpretability for isotope-resolved NMR experiments and supports unambiguous identification of labeled backbone positions in peptide fragments. The Fmoc-protected amino acid format enables preparation of defined peptide contexts rather than relying on post-labeling strategies that may scramble labeling patterns. The labeled peptides and derived fragments generated from this building block can be used as reference materials for spectral libraries, fragmentation mapping, and structure elucidation of peptide conformers.

3. Protected Amino Acid Intermediate

Fmoc-[15N]Val-OH is suitable for protected amino acid chemistry where orthogonality between N-protection and carboxyl reactivity is required. The Fmoc group provides a removable protecting strategy compatible with common peptide synthesis conditions, while the free carboxylic acid allows conversion to activated esters or direct coupling partners in solution-phase synthesis. The isotopically labeled nitrogen remains embedded in the peptide backbone upon coupling, preserving the 15N tag through subsequent transformations. The compound therefore serves as a chiral, isotope-stable intermediate for fine chemical synthesis of labeled peptides, peptide mimetics, and isotope-tagged building blocks for downstream derivatization.

4. Biochemical Research Labeling

Fmoc-[15N]Val-OH is used in chemical biology and biochemical research to generate isotope-labeled peptide substrates, tracers, or internal standards for studying peptide recognition and processing. The valine residue can be positioned within peptide sequences to probe enzyme specificity, cleavage site preferences, or binding interactions where backbone nitrogen signals are experimentally accessible. The Fmoc-protected amino acid format supports reliable incorporation into sequence-defined constructs, enabling consistent labeling across experimental batches. The resulting labeled biomolecular reagents can be employed for quantitative analytical comparisons, mechanistic interpretation, and isotope-resolved monitoring of peptide transformations in biochemical assays.

5. Process Chemistry For Labeled Fine Chemicals

Fmoc-[15N]Val-OH can be employed in process chemistry for manufacturing isotope-tagged fine chemicals and research intermediates with defined stereochemistry and labeling integrity. The combination of Fmoc protection and a free carboxylic acid supports scalable peptide-building-block workflows that minimize isotopic dilution and maintain the 15N label through coupling steps. The valine side chain provides a predictable hydrophobic residue identity that is compatible with automated synthesis and sequence assembly strategies. The compound thus supports industrially relevant production of labeled peptide reagents used as analytical standards, reference materials, and isotope-tagged components in research supply chains.

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